Positron emission tomography (PET) is a nuclear medicine molecular imaging technique, which images the human body in real time, and shows rapid growth in the medical imaging market as an effective human body imaging technique, which can detect biochemical and physiological changes occurring in the human body at the beginning of a disease. The early researches of PET pharmaceuticals for a new disease use 11C, which is a positron emission radioactive isotope, since labeling is relatively easy, and 11C is a carbon, which is a framework of an organic substance. However, since 11C has the short half life of 20 minutes, it is not suitable for commercial use.
Meanwhile, 18F, which is another radioactive isotope, has various superior properties, for example, in that it can be easily produced in a large scale from a cyclotron. Especially, since 18F has the relatively long half life of 110 minutes, it has been recently spotlighted as a commercially applicable nuclide. Due to the utility of 18F, in order to substitute a conventionally developed 11C-labeled compound with an 18F-labeled compound or introduce 18F to a newly developed disease-target compound, there has been generally used a method for introducing a [18F]fluoroprophyl functional group. However, a radiopharmaceutical, to which the [18F]fluoroprophyl functional group is introduced, shows the tendency of decrease in the bonding force to a target material. Due to increase of lipophilicity, high intake occurs in some tissues. Due to increase of non-specific bonding, selectivity is reduced, and thereby, deteriorating an image. These problems can be resolved by introducing a [18F]fluoromethyl group, which is similar in structure to a [11C]methyl group, instead of the [18F]fluoroprophyl functional group.
The conventional method for introducing a [18F]fluoromethyl group uses a [18F]fluoromethylated reagent. This reagent can be generally obtained by labeling 18F to a methane compound having at least two leaving groups. When the reagent is subjected to a nucleophilic substitution reaction with a precursor, a desired radiopharmaceutical, to which a [18F]fluoromethyl group has been introduced, can be prepared. However, this method requires a two-step synthesis process for the 18F labeling, and thereby, causing complexity in process and lengthening the preparation time. The complicated preparation process makes it difficult to realize an automatic synthesis system necessary for commercialization.